Method for controlling the liquid level in vapor condensation pumps



1932- L. FLEISCHMANN ET AL 1,840,496

METHOD FOR CONTROLLING THE LI QUID LEVEL IN VAPOR CONDENSATION PUMPS Filed April 6, 1928 25 7D HEATING CURRENT SOURCE V/ m 6 n s m w v r t tC ID l A e m v t .w nls e e h n10 T .mC L b Patented Jan. 12, 1932 UNITED STATES PATENT OFFICE LIONEL FLEISCHMANN, OF BERLIN-GRUNEWALDE, AND CHRISTIAN KRAMER, QF BER- LIN-PANKOW, GERMANY, ASSIGNORS TO GENERAL ELECTRIC COMPANY, A COR- PORATION OF NEW YORK METHOD FOR CONTRQLLIN'G THE LIQUID LEVEL IN VAPOR CONDENSATION PUMPS Application filed April 5, 1928, Serial No. 268,020, and in Germany June 7, 1927.

stant.

Under operating conditions it is possible for mercury from the rectifier to be added to the supply already in the pump, or vice versa. One of the main reasons for this is a variation of the operating temperatures of the two devices. If for example the rectifier is operating at a higher than normal temperature some of the mercury vapor is drawn into the pump where it is condensed and added to the supply of mercury therein. The opposite action takes place if the pump is being overheated so that all the vapor is not condensed therein and some is forced into the rectifier.

According to present practice the rectifier and pump are made of steel and no means are provided to indicate the amount of mercury in the pump. If the pump does not contain the correct amount of mercury it will not function properly and the pressure within the rectifier will rise to a point where the apparatus must be shut down by protective devices to avoid damage. The main object of our invention is, to provide improved means for regulating the level, or the quantity, of the mercury in the condensation pump.

The features of our invention which are believed to be novel and patentable are set forth in the appended claims. Our invention itself, however, will best be understood by reference to the following specification when considered in connection with the accompanying drawings in which Fig. 1 is a diagrammatic cross-section view of a rectifier and pump, in which according to our invention, means are provided for automatically maintaining the level of the mercury in the pump at a predetermined level.

Fig. 2 is a cross section view of a pump provided with indicating means arranged to indicate the mercury level in the evaporating chamber of the pump. If the mercury level in the pump, is indicated to be incorrect, the respective operating temperatures of the two devices may be changed so that enough mercury is forced out of or sucked into the pump to correct the level.

Fi is also a cross-section of the mercury pump having means to correct the mercury level therein, including a closed vessel containing air and mercury and a tube connection between this vessel and the pump.' The vessel may be moved in respect to the pump in accordance with the mercury level in the container. The regulation of the level in the pump takes place in accordance with the position of the vessel 29.

Fig. l is similar to Figs. 2 and 3. In this arrangement means are provided for indi cating the correct level of the mercury in the pump regardless of the pressure therein. A closed vessel partly fiiled with mercury is also provided and arranged so that mercury may be forced into the pump from this vessel or vice versa.

Referring to the drawings in detail, 10 indicates the mercury-arc rectifier tank. VVithin sleeves 11, attached to the tank are anodes 12 connected to each other through transformer winding 13 the center of which is the negative side of the direct current circuit. At the bottom of tank 10 and insulated therefrom isa pool of mercury 14-, which is the cathode-electrode and constitutes the positive side of the direct current circuit. Surrounding the tank 10 is a jacket 15 through which cooling water circulates. A condensation vacuum pump 16 is connected to tank 10 through pipe 17. The pump 16 includes a condensing chamber 18, an evaporating chamber 19 which contains the mercury the levei of which should be maintained constant, and a heater for evaporating this mercury. The heater includes a resist-or 35 mounted below; the evacuated chamber 19 and heated by current from a suitable source. The vapor from chamber 19 passes into chamber 18 through pipe 20 and nozzle 21. Chamber 18 is surrounded by jacket 22 through which cooling water circulates. This causes a condensation of the vapor coming from nozzle 21 and thereby creates the low pressure area into which the gases from the tank 10 are drawn. The gases thus pumped from tank 10 are dlscharged through pipe 24 into a roughing pump 23. The condensed mercury flows back into chamber 19 through pipe 25.

A second pipe connection 26 is provided between cathode 14: and chamber 19, to enable mercury to How in either direction. pump 16 is then so mounted that under normal operating conditions the level of the cathode and the level of the mercury in the ump will be in equilibrium and no flow ex ists in the pipe 26. If then any of the mercury from the cathode is added to the pump supply or vice versa, in a manner explained above, the two levels are unbalanced until the flow through pipe 26 again establishes the equilibrium.

Fig. 2 is a cross section view of pump 16. At the lower end of chamber 19 a glass tube 27 is inserted. When the tube is inserted it is turned down into the position shown by dotted lines, and completely filled with mercury.

It is then turned up into the vertical position, in which it is shown, and the mercury within it falls to a level corresponding to the mercury level in the chamber 19. It then,

the level in this tube 27 is above or below normal the operator regulates the flow of the cooling water in therespective jackets thereby regulating the operating temperatures and causing mercury to be transferred from one device to the other as. previously explained.

Fig. 3 shows a cross section of the pump 16 having inserted a tube 28 in the bottom of chamber 19. A closed vessel 29 containing mercury and air is attached to the other end of this tube. This vessel 29 is movable in respect to the pump 16 and is arranged to indicate the mercury level within it. The weight of the mercury within chamber 19 controls the level of the mercury in vessel 29 since it compresses the air in vessel 29 to a greater or lesser degree. It according to this indication the mercury level in the pump is abnormal the vessel may be moved up or down in respect to pump 16, and the mercury level in chamber 19 thereby regulated.

Fig. 4 is similar to Figs. 2 and 3 but has a tube, inserted at the upper end of chamber 19, connected to tube 31 at the lower end, by a. glass tube 32. This arrangement provides a level indication independent of the pressure in chamber 19. Tube 31 leads into a closed vessel 33 which contains mercury.

Another tube 34 also leads into vessel 33 and The may be either connected to a compressed air source or a vacuum source depending upon whether mercury is to be forced into, or drawn out of chamber 19.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. The combination of a device including a tank containing a vaporizable liquid electrode, a vapor condensation pump, said pump having a connection with said tank for evacuating said tank, a vaporizable liquid in said pump, heating means to vaporize the liquid in said pump, and meansincluding a second connection for the flow of liquid between said pump and said electrode to maintain the level of the liquid in the pump and in the liquid electrode in equilibrium under normal operating conditions, and to lower the level of the liquid in said pump to normal level when said level is raised by vapor from said electrode passing from said tank to said pump and to. raise said level to normal level when said level is lowered by vapor passing from said pump to said tank.

2. The combination of a device including a tank containing a vaporizable liquid electrode, a vapor condensation pump, said pump having a connection with said tank for evacuating said tank, a vaporizable liquid in said pump, heating means to vaporize the liquid in said pump, and means including a second connection for the flow of liquid between said pump and said electrode to lower the level of the liquid in said pump when said level is raised by vapor passing from said tank to said pump and to raise said level when said level is lowered by vapor passing from said pump to said tank, whereby said liquid in said pump is maintained at a predetermined level with respect to the level of said electrode.

In testimony whereof we have hereunto set opr hands this 19th day of March, 1928.

LIONEL FLEISCHMANN.

CHRISTIAN KRAMER. 

